she's here with us in japan, as well. christiane? >> reporter: david, this morning, japan is on high nuclear alert. as the government races to cool down two nuclear reactors. and the government is also racing to save lives. it has doubled its rescue operation from 50,000 personnel to 100,000. with search and rescue operations now under way in many parts of the earthquake/tsunami zone, we wonder how much of the country is effected by this kind of chaos and destruction. the helicopter's taking on fuel and we're going up to the sendai earthquake zone. japan is not a massive country, but part of that sendai area is quite remote. some of the roads have been damaged. there are mountains in the greater area around there, and that's hampering not just assessment, but also relief and the delivery of supplies. on the hour-long ride to the city of sendai, near the epicenter, little evidence of the earthquake. much of the countryside appears unscathed. but as the chopper turns to the coast, the full extent of the devastation reveals itself. huge